[tip: sched/core] sched/debug: Add new tracepoint to track compute energy computation

[tip-bot2 for Qais Yousef]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     15874a3d27e6405e9d17595f83bd3ca1b6cab16d
Gitweb:        https://git.kernel.org/tip/15874a3d27e6405e9d17595f83bd3ca1b6cab16d
Author:        Qais Yousef <qyousef@xxxxxxxxxxx>
AuthorDate:    Sun, 17 Sep 2023 00:29:55 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 29 Sep 2023 10:29:18 +02:00

sched/debug: Add new tracepoint to track compute energy computation

It was useful to track feec() placement decision and debug the spare
capacity and optimization issues vs uclamp_max.

Signed-off-by: Qais Yousef (Google) <qyousef@xxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230916232955.2099394-4-qyousef@xxxxxxxxxxx
---
 include/trace/events/sched.h | 5 +++++
 kernel/sched/core.c          | 1 +
 kernel/sched/fair.c          | 7 ++++++-
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbb99a6..a13d5d0 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -735,6 +735,11 @@ DECLARE_TRACE(sched_update_nr_running_tp,
 	TP_PROTO(struct rq *rq, int change),
 	TP_ARGS(rq, change));
 
+DECLARE_TRACE(sched_compute_energy_tp,
+	TP_PROTO(struct task_struct *p, int dst_cpu, unsigned long energy,
+		 unsigned long max_util, unsigned long busy_time),
+	TP_ARGS(p, dst_cpu, energy, max_util, busy_time));
+
 #endif /* _TRACE_SCHED_H */
 
 /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 84881a5..324980e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -114,6 +114,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_cfs_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_se_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_compute_energy_tp);
 
 DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 284b0ab..e2a69af 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7600,11 +7600,16 @@ compute_energy(struct energy_env *eenv, struct perf_domain *pd,
 {
 	unsigned long max_util = eenv_pd_max_util(eenv, pd_cpus, p, dst_cpu);
 	unsigned long busy_time = eenv->pd_busy_time;
+	unsigned long energy;
 
 	if (dst_cpu >= 0)
 		busy_time = min(eenv->pd_cap, busy_time + eenv->task_busy_time);
 
-	return em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+	energy = em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+
+	trace_sched_compute_energy_tp(p, dst_cpu, energy, max_util, busy_time);
+
+	return energy;
 }
 
 /*